Lymphoid and Immunity System

Ns. Rinik Eko kapti M. Kep.Lymphoid and Immunity SystemPathogenThe lymphoid systemDefense mechanism: non specific defense specific defenseLymphoid SystemLymphLymphaticLymphoid tissueLymphocytes

Function of lymphoid system: production, maintenance, distribution of lymphocytes that provide defenseMost of the bodys lymphocytes are produced and stored within: lymphoid tissue, lymphoid organ and red bone marrowTo provide an effective defense: able to detect problems, able to reach the side of injury or infection area

Able to enter and leave capillaries to supply the tissueLymphatic vesselsCarry lymph from peripheral tissue to the venous systemLymphatic capillary The lymphatic network begins with lymphatic capillaryPresent in almost every tissue and organ in the bodyAbsent in areas that lack a blood supply, bone marrow and the central nervous systemSmall lymphatic vesselsFrom lymphatic capillaries, lymph flows into larger lymphatic vessels that lead toward the body trunkLymphatic vessels commonly occur in association with blood vesselsLymphocytes 20-30% of the circulating leukocyte populationOnly a small fraction of the total lymphocyte populationType of lymphocytesT (thymus dependent) cellB (bone marrow derived) cellNK (natural killer) cellT (thymus dependent) cell

80% of circulating lymphocytes are classified as T cellTypes of T cell:Cytotoxic T cells --- attack foreign cells or body cells infected by viruses. Commonly direct contact. The primary cell involved in the production of cell mediated immunity or cellular immunityHelper T cells --- stimulate the activation and function of both T and B cellsSuppressor T cells --- inhibit the activation and function of both T and B cellsB (bone marrow derived) cell10-15% of circulating lymphocytesWhen stimulate, B cell can differentiate into plasma cells, which are responsible for the production and secretion of antibodies (immunoglobulin)B cells are responsible for antibody mediated immunity, which is also known as humoral (liquid) immunity because antibodies occur in body fluid.NK (natural killer) cell5-10% of circulating lymphocytesAttack foreign cell, normal cell infected virus, and cancer cellImmunological surveillanceLymphocyte have relatively long live spans80% ---- survive 4 yearsSome last 20 years or more

The derivate and distribution of lymphocyte

Lymphoid TissuesConnective tissues dominated by lymphocyteMALTThe collection of lymphocyte tissue linked with the digestive systemTonsilsLarge lymphoid nodules in the walls of the pharynx

Lymphoid OrgansA fibrous connective tissue capsuleThe limp nodesPurifying lymph before reaches the venous circulationThe ThymusProduces several hormones that are important to the development and maintenance of normal immunology systemThe SpleenThe removal of abnormal blood cells and other bloods component by phagocytosisThe initiation of immune responses by B cells and T cells in response to antigens

Body DefenseThe human body has multiple defense mechanisms that together provide resistanceThe ability to fight infection, illness, and deseaseBody defenses can be sorted into 2 general catagories:Non specific defensesSpecific defensesNon specific defenses

Prevent the approach, deny the entry or limit the spread of microorganism or other environment hazard Do not distinguish one type of threat from anotherTheir response is the same regardless of the type of invading agent these defense are present at birth

7 major categories of Non specific defensesPhysical barrierPrevent approach of and deny access to pathogenFor example: skinPhagocytesRemove debris and pathogenMacrophage, neutrophil, Eosinophil, monocyteImmunological surveillanceDestroy abnormal cellNatural killer cellcontinueInterferon Increase resistance of cells to viral infection, slow the spread of diseaseInterferon released by activated lymphocyte, macrophage, or virus-infected cellsComplementAttack and break down cell walls, attracts phagocytes, stimulates inflammation

continueThe inflammatory responseMultiple effectBlood flow increased Phagocytes activatedCapillary permeability increasedClotting reaction walls off regionRegional temperature increasedSpecific defenses activatedInflammation Process

continueFeverMobilizes defense, accelerate repairs, inhibit pathogenBody temperature rises in response to pyrogenPyrogen can reset this thermostat and raise the temperatureThe pyrogen released by active macrophages is a cytokine called endogenous pyrogen or interleukin-1A fever can be beneficialHigh temperature may inhibit some viruses and bacteria temperature --- body metabolismCell can move faster, enzymatic reactions occur faster. ----- quicker mobilization of tissue defense and accelerated repair process

Specific Defenses or ImmunityProvided by the coordinated activities of T and B cellT cell --- cellular immunity(abnormal and pathogen inside cell)B cell --- humoral immunity (antigen and pathogen in body fluid)

Form of immunity

Properties of immunitySpecifityVersatilityMemoryTolerance

T cell in immune responseBefore the immune response can begin, T cell must be activated by exposure to an antigenAntigen presentation ---- antigen recognition ---- activation of CD8 T cells/activation of CD4 T cellAntigen presentationAntigen bound to glycoprotein in plasma membrane (HMC protein/HLAs)2 major classes of HMCClass 1 HMC --- in membranes of all nucleated cellClass 2 HMC --- only in the membrane of antigen presenting cells (APC) and lymphoside. APC responsible for activating T cell defense.

Antigen recognitionT cell respond to antigen held by class 1 or 2 depend o structure of the plasma membraneThe membran protein involved are members of a large class of protein called CD markerLymphocyte, macrophages and other releted cell have CD markerAll of T cell have CD 3 receptor complex2 other CD markerCD8 markerFound on cytotoxic T cells and suppressor T cellsRespond to antigen presented by class 1CD4 markerFound on helper T cellsRespond to antigen presented by class 2

activation of CD8 T cells

B cell in immune responseResponsible for launching a chemical attack on antigen by producing appropriate and specific antibody3 Step:SensitizationActivationDivision and differentiationThe antigen antibody complex

The sensitization and activation of B cells

Antibody structureImmunoglobulin GImmunoglobulin EImmunoglobulin DImmunoglobulin MImmunoglobulin A

Actions of antibodyNeutralizationPrecipitation and agglutinationActivation of complementAttraction of phagocytesOpsonizationStimulation of inflammationPreventive of bacterial and viral adhesionTerimakasih